Wireless occupancy sensing with portable power switching

ABSTRACT

A system may include a wireless receiver to receive a wireless signal from an occupancy sensor and at least one power switch to control power to at least one load in response to the wireless signal, where the wireless receiver and power switch are included in a local switching device, and where the local switching device comprises a power pack having a housing, a power supply to convert high-voltage power to a low-voltage source for operating internal circuitry in the power pack, and switch control logic to implement an unoccupied delay time.

RELATED APPLICATION

This application claims priority and is a divisional application of U.S.patent application Ser. No. 12/503,381 titled WIRELESS OCCUPANCY SENSINGWITH PORTABLE POWER SWITCHING, filed Jul. 15, 2009, all which isincorporated by reference.

BACKGROUND

Occupancy sensing technologies are used to monitor the presence of humanoccupants in indoor and outdoor spaces. Occupancy sensing systemsconserve energy by automatically turning off lighting and otherelectrical loads when the space is unoccupied. They may also perform aconvenience function by automatically turning on lighting and otherloads when an occupant enters a space.

An occupancy sensing system generally includes at least two majorcomponents: an occupancy sensor and a switching device. The sensorgenerally needs to be positioned in a location that is selected to havea clear view of the entire space that is to be monitored for occupants.This type of location, however, is typically not convenient for theswitching device. Therefore, occupancy sensor systems generally includecontrol wiring that runs between the occupancy sensor and the switchingdevices. This additional wiring tends to be expensive and time consumingto install. It may also be a source of system failures that aredifficult to diagnose if the wiring is concealed in walls. Moreover,once the wiring is installed, it is difficult to reconfigure the systemif there is a change in the type or location of loads that are to becontrolled by the occupancy sensor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an embodiment of a wireless occupancy sensing systemhaving a portable switching device according to some of the inventiveprinciples of this patent disclosure.

FIG. 2 illustrates another embodiment of a wireless occupancy sensingsystem having a portable switching device according to some of theinventive principles of this patent disclosure.

FIG. 3 illustrates an embodiment of a wireless occupancy sensing systemhaving two or more portable switching devices according to some of theinventive principles of this patent disclosure.

FIG. 4 illustrates an example technique for processing a signal from adetector according to some of the inventive principles of this patentdisclosure.

FIG. 5 illustrates another example technique for processing a signalfrom a detector according to some of the inventive principles of thispatent disclosure.

FIG. 6 illustrates an embodiment of a wireless occupancy sensoraccording to some of the inventive principles of this patent disclosure.

FIG. 7 illustrates an embodiment of a portable switching device for usein a wireless occupancy sensing system according to some of theinventive principles of this patent disclosure.

FIG. 8 illustrates an embodiment of a wireless occupancy sensoraccording to some of the inventive principles of this patent disclosure.

FIG. 9 illustrates an embodiment of a power strip having portable powerswitching for an occupancy sensing system according to some of theinventive principles of this patent disclosure.

FIG. 10 illustrates an embodiment of a portable power switching devicefor an occupancy sensing system according to some of the inventiveprinciples of this patent disclosure.

FIG. 11 illustrates an embodiment of a portable power switching devicefor an occupancy sensing system according to some of the inventiveprinciples of this patent disclosure.

FIG. 12 illustrates an embodiment of an appliance having portable powerswitching for an occupancy sensing system according to some of theinventive principles of this patent disclosure.

FIG. 13 illustrates an embodiment of a local power switch for a wirelessoccupancy sensing system according to some of the inventive principlesof this patent disclosure.

FIG. 14 illustrates another embodiment of a local power switch for awireless occupancy sensing system according to some of the inventiveprinciples of this patent disclosure.

DETAILED DESCRIPTION

Some of the inventive principles of this patent disclosure relate to theuse of a portable switching device in a wireless occupancy sensingsystem.

FIG. 1 illustrates an embodiment of a wireless occupancy sensing systemhaving a portable switching device according to some of the inventiveprinciples of this patent disclosure. The system of FIG. 1 includes aportable switching device 10 to control the flow of power from abuilding wiring system 12 to an electrical load 14 in response to awireless signal 16 received from an occupancy sensor 18.

The portable switching device 10 may be portable in the sense that itmay be removed from an interior or exterior building space withoutdisconnecting any permanent building wiring. For example, the portableswitching device may be implemented with a cord-connected power stripthat may be removed from a first office by unplugging it from areceptacle and moved to second office. As another example, the portableswitching device may be implemented with a screw-base adapter that maybe connected between a light bulb and a screw-type light socket.

In some embodiments, the wireless signal from the occupancy sensor maybe implemented as an occupancy signal that provides a relativelyhigh-level indication of whether the monitored space is occupied or not.For example, the wireless signal may be encoded as a binary signal whereone state indicates the space is occupied, and the other state indicatesthe space is not occupied. A binary occupancy signal may haverefinements such as a delay time integrated into the signal, i.e., thesignal does not switch from the occupied to the unoccupied state untilthe space has been unoccupied for the entire duration of the delay time.

In other embodiments, the wireless signal from the occupancy sensor maybe implemented as a detector signal that provides a relatively low-levelindication of a physical stimulus being sensed by a detector in theoccupancy sensor. For example, in an occupancy sensor that uses passiveinfrared (PIR) sensing technology, the wireless signal may be encoded totransmit primitive signals or raw data from the PIR detector. Suchsignals or data may then be processed in the portable switching deviceto determine whether the monitored space is occupied.

In this and any other embodiments, the wireless signal from theoccupancy sensor may be transmitted in any suitable form, for example,radio frequency (RF) signals, infrared (IR) signals, ultrasonic signals,etc.

FIG. 2 illustrates another embodiment of a wireless occupancy sensingsystem having a portable switching device according to some of theinventive principles of this patent disclosure. In the system of FIG. 2,the portable switching device 20 may be configured to control power totwo separate loads 22 and 24 independently in response to the wirelesssignal from the occupancy sensor. For example, in some embodiments, oneof the loads may always be energized, or may be controlled by a masterswitch, while the other load may be controlled by the wireless signalfrom the occupancy sensor. In other embodiments, both loads may becontrolled by the wireless signal from the occupancy sensor, but withdifferent delay times, different levels of sensitivity, etc. In yetother embodiments, one of the loads may be controlled by the wirelesssignal from the occupancy sensor, while the other load may be controlledby a combination of an ambient light detector, as well as the wirelesssignal from the occupancy sensor.

FIG. 3 illustrates an embodiment of a wireless occupancy sensing systemhaving two or more portable switching devices according to some of theinventive principles of this patent disclosure. In the system of FIG. 3,two different portable switching devices 26 and 28 may be configured tocontrol power to two separate loads 30 and 32 in response to thewireless signal from the occupancy sensor. For example, in someembodiments, the first portable switching device 26 may be implementedwith a screw-base adapter to turn off a task light as soon as anoccupant has left a cubical that is monitored by the occupancy sensor,but the second portable switching device 28 may be implemented with apower strip configured to turn off a computer monitor and printer30-minutes after the occupant has left the cubical.

FIG. 4 illustrates an example technique for processing a signal from adetector according to some of the inventive principles of this patentdisclosure. In the embodiment of FIG. 4, a signal processor 34 isincluded in an occupancy sensor 36 to process signals from a detector38. The signal processor may include all of the functionality to processa raw signal from the detector, as well as logic to make the finaldetermination of whether the monitored space should be consideredoccupied.

For example, with an occupancy sensor based on PIR sensing technology,the detector 38 may include a semiconductor chip with one or morepyroelectric detectors that generate a voltage that changes in responseto changes in the amount of infrared energy in the field of view. Inthis example, the signal processor 34 may include amplifiers,comparators, logic, etc. to determine whether a change in the amount ofinfrared energy is caused by the motion of an actual occupant or by someother source of infrared energy such as background energy from ambientlight. The signal processor may also include logic to implement featuressuch as a delay time to prevent false unoccupied readings. The finaloutput from the signal processor is a binary occupancy signal thatindicates whether the monitored space is occupied or unoccupied. Theoccupancy signal is transmitted as the wireless signal 40 to a portableswitching device 42.

Although the example of FIG. 4 is shown with only one detector, multipledetectors may be used. For example, some embodiments may include bothPIR and ultrasound detectors, in which case, the signal processor mayinclude circuitry to process changes in the output of the PIR detector,as well as detecting Doppler shift in the output from an ultrasoundtransducer. The signal processor may also include logic to make thefinal occupancy determination by combining the information from the PIRand ultrasound detectors.

In the embodiment of FIG. 4, and in any other embodiments, the signalprocessor 34 and any other circuitry and/or logic may be implemented inanalog and/or digital hardware, software, firmware, etc., or anycombination thereof.

FIG. 5 illustrates another example technique for processing a signalfrom a detector according to some of the inventive principles of thispatent disclosure. In the embodiment of FIG. 5, the signal processor 44is moved to the portable switching device 48. Rather than transmittingan occupancy signal, the occupancy sensor 50 transmits a detector signalthat provides a relatively low-level indication of a physical stimulusbeing sensed by the detector 52 in the occupancy sensor. For example, inan occupancy sensor that uses PIR sensing technology, the occupancysensor may transmit the value of the voltage output from the PIRdetector in analog or digital form on the wireless signal 54. The signalprocessor 44 in the portable switching device 48 may then perform theprocessing to determine whether a change in the amount of infraredenergy received at the detector 52 is caused by the motion of an actualoccupant. The signal processor 44 may also include logic to implementfeatures such as a delay time, sensitivity adjustment, etc. The portableswitching device 48 then uses the occupancy determination to control theflow of power to an electrical load 14.

In some embodiments, the signal processing functions may be distributedbetween multiple components. For exampled, the occupancy sensor mayinclude some rudimentary signal processing in which the detector signalis converted to a digital form with an analog-to-digital converter(ADC). In such an embodiment, some amount of filtering may be includedin the occupancy sensor as well. The digitized detector signal may thenbe transmitted to the portable switching device where additional signalprocessing circuitry may complete the processing to make the occupancydetermination.

In other embodiments, signal processing for multiple detectors may bedistributed between multiple components. For example, with an occupancysensor that uses a combination of PIR and video sensing, the signalprocessing for the PIR detector, which may require relatively littleprocessing power, may be performed at the occupancy sensor, whileprocessing for the video detector, which may require more processingpower, may be performed at the portable switching device. In thisexample, the wireless signal may include a binary occupancy signalrelating to the PIR portion, and a more complex detector signal relatingto the video portion. Logic at the portable switching device may combinethe binary PIR occupancy signal with the output from the videoprocessing to make a final occupancy determination.

FIG. 6 illustrates an embodiment of a wireless occupancy sensoraccording to some of the inventive principles of this patent disclosure.The system of FIG. 6 includes a detector 56 and a wireless transmitter58. In some embodiments, the detector may be coupled directly to thetransmitter to transmit the detector signal as a relatively low-levelindication of a physical stimulus sensed by a detector, for example, bytransmitting a primitive signal or raw data from the detector on thewireless signal 66. In other embodiments, the occupancy sensor mayinclude a signal processor 60 to process the detector signal anddetermine whether the space monitored by the detector is occupied. Insuch an embodiment, the signal processor may output a binary occupancysignal that is transmitted as the wireless signal 66 and indicateswhether the monitored space is occupied or unoccupied. The signalprocessor may include logic to implement additional features such as adelay time, variable sensitivity, etc.

The occupancy sensor may also include one or more additional detectors62. In some embodiments, the output of an additional detector may becoupled directly to the transmitter 58, while in other embodiments, theoutput of an additional detector may be processed by the signalprocessor 60. Alternatively, one or more additional transmitters may beincluded to transmit the output signal for one or more additionaldetectors, with or without subjecting the detector signal to signalprocessing.

The transmitter 58 may transmit the wireless signal 66 using anysuitable wireless transmission technology. Examples include infraredtransmission using a standard from the Infrared Data Association (IrDA),RF transmission using one of the many standards developed by theInstitute of Electrical and Electronic Engineers (IEEE), or any otherstandardized and/or proprietary wireless communication technology.

A user interface 68 may be included to enable a user to configure thesystem, adjust parameters, etc. For example, the user interface mayenable a user to set an unoccupied delay time, detector sensitivity,learn mode, etc. A user interface may be implemented with any level ofsophistication from a simple push-button switch with no user feedback toa keypad with full text display, etc.

A power source 64 provides power to operate some or all of the variouscomponents of the occupancy sensor. In some embodiments, the powersource may be provided from an external source, for example, by ahardwired connection to a 24 VDC power supply, a 120 VAC branch circuit,etc. In other embodiments, the power source may be internal, forexample, one or more batteries, fuel cells, photovoltaic cells, etc.Other embodiments may include combinations of these various types ofpower sources. For example, primary power may be provided by a 120 VACcircuit, which maintains a backup battery in a charged state to providepower in the event of a loss of the 120 VAC circuit.

FIG. 7 illustrates an embodiment of a portable switching device for usein a wireless occupancy sensing system according to some of theinventive principles of this patent disclosure. The system of FIG. 7includes a wireless receiver 70 to receive a wireless signal from anoccupancy sensor using any suitable wireless transmission technologies,including those discussed above. A signal processor 72 may be includeddepending on the nature of the wireless signal. If the wireless signalis implemented as an occupancy signal that provides a relativelyhigh-level indication of whether the monitored space is occupied, thesignal processor may be omitted. In other embodiments, if the wirelesssignal from the occupancy sensor is implemented as a detector signal thesignal processor may be included to process the detector signal anddetermine whether the monitored space is occupied.

Switch control logic 74 controls a power switch 76 in response to anoccupancy signal from the receiver and/or the signal processor. Theswitch control logic 74 may also control one or more additional powerswitches 78. A power switch may include any suitable form of isolated ornon-isolated power switch including an air-gap relay, solid state relay,or other switch based on SCRs, triacs, transistors, etc. The switch mayprovide power switching in discrete steps such as on/off switching, withor without intermediate steps, or continuous switching such as dimmingcontrol.

A user interface may be included to enable a user to configure thesystem, adjust parameters, etc. For example, the user interface mayenable a user to set an unoccupied delay time, detector sensitivity,learn mode, etc. As with the occupancy sensor as described above, a userinterface on a portable switching device may be implemented with anylevel of sophistication from a simple push-button switch, to a keypadwith full text display, etc. For example, in some embodiments, a userinterface may include a trimming potentiometer (trim pot) to set a delaytime for unoccupied mode.

The power connections to the power switches may be implemented in anysuitable form. For example, in some embodiments, the input powerconnection 82 may include a standard grounded or ungrounded power cordwith a plug for connection to a wall receptacle. In other embodiments,the input power connection may include a screw base to connect theswitching device to a standard screw-type light socket. In embodimentsthat include more than one power switch, additional power inputs 84 maybe connected to the same or separate input power connections.

Since the portable switching device of FIG. 7 includes at least onepower connection 82 or 84, one of these connections may be utilized as asource of power to operate the wireless receiver, signal processor, userinterface, logic, etc. Alternatively, a separate power source such asone or more batteries, PV cells, etc. may be used as a primary orback-up source of power to operate this circuitry.

The connection from a power switch to a load may also be implemented inany suitable form. For example, in some embodiments, the connection 86from the switch 76 may include a receptacle for a standard power plug, aground fault circuit interrupter (GFCI), a screw socket for a standardlight bulb or other type of lamp holder, etc. In an embodiment havingtwo power switches in a power strip, one of the switches may beconfigured to switch power to one or more receptacles in response to thewireless signal from an occupancy sensor under control of the switchcontrol logic, while the other switch may be configured to switch aseparate group of receptacles on at all times, or only turn off inresponse to a master on-off switch on the power strip.

In another embodiment having two power switches in a power strip, thetwo switches may both be configured to be controlled by the wirelesssignal from an occupancy sensor, but the switch control logic may causethe two switches to control separate groups of receptacles on the powerstrip with different delay times.

In some other embodiments, the switch control logic may also beconfigured to provide various types of overrides such as manual or timeroverrides of the occupancy sensor for certain loads. For example, on apower strip, a specific receptacle for a coffee maker may be configuredto remain energized for a fixed length of time, regardless of occupancy,to assure a completely brewed pot of coffee. The user interface may beconfigured to enable a user to select a specific receptacle anddesignate the override time and other parameters.

As another example with a power strip, a receptacle for a networkedprinter that is normally controlled by the occupancy sensor may bemanually and temporarily overridden to remain on, for example, if theoccupant knows that others will be sending network print jobs to theprinter while the occupant is away from the monitored space.

As yet another example with a power strip, one group of receptacles fordevices such as a monitor, printer, background music, etc., may beconfigured to turn off after the monitored space is unoccupied for 10minutes, while a second group of receptacles for devices such as acomputer CPU may be configured to turn off after the monitored space isunoccupied for one hour.

As with other embodiments, the logic and circuitry in the embodiment ofFIG. 7 may be implemented with analog and/or digital hardware, software,firmware, etc., or any combination thereof.

FIG. 8 illustrates an embodiment of a wireless occupancy sensoraccording to some of the inventive principles of this patent disclosure.The embodiment of FIG. 8 includes a PIR detector 92 in a housing 90 thatmay be mounted permanently to a building with screws, clips, glue, etc.,mounted temporarily to a building, for example, with removable orrepositionable two-sided tape, hook-and-loop fasteners, etc., or leftunattached on a shelf, desk, cabinet, etc., in a location that providesthe PIR sensor with an adequate field of view of the monitored space.

In this example, the occupancy sensor also includes a photovoltaic (PV)cell 100 to provide the primary source of power for the sensor andrecharge one or more batteries on which the occupancy sensor runs wheninadequate ambient light is available. An access cover 98 may provideaccess to controls for the PIR sensing operation such as range,sensitivity, field of interest, learn mode, etc.

In some embodiments, the occupancy sensor may include one or moreadditional detectors 94 and 96 which may include, for example,ultrasonic transducers, audio transducers, etc., or any combinationthereof.

In this embodiment, the occupancy sensor may communicate with one ormore portable switching devices through an RF transmitter which may beenclosed within the housing if it is fabricated from plastic or othermaterial that does not block RF signals. The RF transmitter may beconfigured to flood the entire monitored space with the RF signal toenable any portable switching devices in the space to respond to theoccupancy sensor. In some embodiments, multiple wireless occupancysensors may be configured to operate on different frequencies. In otherembodiments, an occupancy sensor may be configured to send differentwireless occupancy signals on different frequencies, for example,occupancy signals having different delay times may be transmitted by thesame occupancy sensor on different frequencies.

The type of wireless signal or signals transmitted by the occupancysensor may depend on the type, if any, of signal processingfunctionality in the occupancy sensor. As discussed above, in someembodiments with little or no signal processing capacity, the occupancysensor may broadcast a primitive or only slightly processed detectorsignal. In such embodiments, the elimination or reduction of signalprocessing at the occupancy sensor may reduce the power consumed andtherefore, extend the battery life, reduce the size of the PV cell, etc.In other embodiments with more signal processing capacity, the occupancysensor may broadcast a high-level binary occupancy signal.

Although the embodiment of FIG. 8 is shown in the context of an RFtransmitter and PIR or U/S or audio detectors, the inventive principlesmay also be applied to embodiments that use other wireless communicationtechnologies such as infrared and other occupancy sensing technologies.

FIG. 9 illustrates an embodiment of a power strip having portable powerswitching for an occupancy sensing system according to some of theinventive principles of this patent disclosure. The embodiment of FIG. 9includes a housing 102 having a power cord 104 that can be plugged intoa standard power receptacle. A first group of receptacles 108 iscontrolled only by a master switch 106. A second group of receptacles110 is also controlled by the master switch, but may also be controlledby a portable switching device 112 in response to a wireless signal froman occupancy sensor. A wireless receiver 114 receives the wirelesssignal from the occupancy sensor and controls the second group ofreceptacles 110 accordingly. In this embodiment, a user interfaceincludes a trim pot 116, but other embodiments may include apotentiometer with a knob, an optical encoder, a keypad and display, orany other type of user interface, or no user interface. The trim pot 116in this embodiment enables a user to set a custom time delay for theswitches receptacles 110.

In other embodiments, two or more groups of receptacles may be arrangedto turn off with different time delays in response to a wireless signalfrom an occupancy sensor. For example, one group of receptacles may beconfigured to turn off with a short time delay after the monitored spacebecomes unoccupied, while another group of receptacles may be configuredto turn off with a longer time delay. Such an embodiment may include auser interface with two separately operable user inputs for setting thetime delay. Alternatively, one time delay may be pre-programmed or hardwired into the power strip, while a use is able to adjust the other timedelay. In one example of an end-user configuration, a power strip withmultiple groups of receptacles may be set up with a task light, printer,and computer monitor plugged into the group that turns off quickly,whereas a computer CPU and coffee mug warmer may be plugged into thegroup having a longer delay time. To facilitate an orderly shutdown ofthe CPU, the power strip or other portable switching device may includea communication interface to transmit a message to the CPU in advance ofpowering down to enable the CPU to initiate a shutdown sequence.

As discussed above, the wireless signal from the occupancy sensor may beimplemented as a high-level occupancy signal, a low-level detectorsignal, or some combination thereof. The portable switching device 112may have any suitable amount of signal processing functionalitydepending on the type of wireless signal transmitted by the occupancysensor. The portable switching device 112 may include switch controllogic to implement any of the control techniques discussed above,including those described with respect to FIG. 7, or any other controltechnique that takes advantage of a wireless signal from an occupancysensor.

FIG. 10 illustrates an embodiment of a portable power switching devicefor an occupancy sensing system according to some of the inventiveprinciples of this patent disclosure. The embodiment of FIG. 10 isconfigured as a light bulb adapter and includes a body 120 having ascrew base 118 that can be mounted in a screw-type lamp socket. Ascrew-in socket 122 enables an incandescent lamp, compact fluorescentlamp (CFL) or other load to be connected to the adapter. A switch in thebody operates in response to a wireless signal from an occupancy sensorreceived by a wireless receiver 124. A dial 126 enables the user tomanually set a custom delay time.

As with the embodiment of FIG. 9, the wireless signal from the occupancysensor may be implemented as a high-level occupancy signal, a low-leveldetector signal, or some combination thereof. The embodiment of FIG. 10may include any suitable amount of signal processing functionalitydepending on the type of wireless signal transmitted by the occupancysensor.

FIG. 11 illustrates an embodiment of a portable power switching devicefor an occupancy sensing system according to some of the inventiveprinciples of this patent disclosure. The embodiment of FIG. 11 isconfigured as a portable in-line power switch and includes a body 128having blades to form a power plug 130 extending from the back of thebody to connect the device to a standard wall receptacle. A receptacle132 is formed in the front of the body. A power switch inside the bodycontrols the flow of power from the plug 130 to the receptacle 132 inresponse to a wireless signal from an occupancy sensor received by awireless receiver 134. A dial 136 enables the user to manually set acustom delay time.

As with the embodiments of FIG. 9 and FIG. 10, the wireless signal fromthe occupancy sensor may be implemented as a high-level occupancysignal, a low-level detector signal, or some combination thereof. Theembodiment of FIG. 11 may also include any suitable amount of signalprocessing functionality depending on the type of wireless signaltransmitted by the occupancy sensor.

FIG. 12 illustrates an embodiment of an appliance having portable powerswitching for an occupancy sensing system according to some of theinventive principles of this patent disclosure. In the embodiment ofFIG. 12, a portable power switching device 140 is integrated directlyinto the appliance 138, which in this example is a task light, but couldbe any other suitable electrical appliance. The portable power switchingdevice 140 is mounted in a base 146 of the task light which may beplugged in to a wall receptacle through a power cord 150. A power switchinside the portable power switching device controls the flow of powerfrom the cord 150 to a lamp 152 in response to a wireless signal from anoccupancy sensor received by a wireless receiver 142. A dial 144 enablesthe user to manually set a custom delay time. A master switch 148 maycompletely de-energize the entire appliance.

As with the embodiments of FIG. 9 through FIG. 11, the wireless signalfrom the occupancy sensor may be implemented as a high-level occupancysignal, a low-level detector signal, or some combination thereof. Theembodiment of FIG. 12 may also include any suitable amount of signalprocessing functionality depending on the type of wireless signaltransmitted by the occupancy sensor.

Some additional inventive principles of this patent disclosure relate tothe use of a time clock in a wireless occupancy sensing system. Anexample is illustrated in the embodiment of FIG. 12 where the applianceincludes a time clock to enable various clock-based control techniquesto be combined with other inventive features. An LCD display 141 andkeypad 143 enable a user to configure the clock and appliance so thatthe appliance operates differently during different time periods. Forexample, the clock may be programmed with a normal schedule such as 8:00am to 5:00 pm on weekdays. The appliance may be configured so that itonly responds to the wireless signal from an occupancy sensor duringnormal work hours, but disregards the wireless signal, i.e., stays off,at other times. A manual override switch 145 may be included to enable auser to manually toggle the on/off state of the appliance during normalworks hours, outside of normal work hours, or at any time.

The time clock may be implemented with any suitable mechanical and/orelectrical platforms. In the embodiment of FIG. 12, the interface to theclock is shown as a display and keypad that enable configuration of theclock which may be implemented with a dedicated microcontroller, or witha microcontroller that implements some or all of the other functions ofthe appliance such as wireless reception, time delay, power switchcontrol, manual override, etc. In other embodiments, the time clock maybe implemented with a rotating mechanical timer with a dial face havingtrippers arranged around the face to trigger on/off events by closingand opening mechanical contacts as the dial face turns. In someembodiments, the clock may include an astronomical adjustment to adjusttime settings based on seasons or time of year. In an electricalimplementation, a clock may be realized with digital and/or analoghardware, software, firmware, etc., or any combination thereof.

The keypad 143 may include left/right select buttons to scroll throughand select parameters, and up/down increment-decrement buttons to changea selected parameter. Example parameters may include time-of-day orday-of week settings, start and end points for control time periods,configuration of power switch response to control time periods, enableor disable manual override, etc.

Although illustrated in the context of an appliance, the inventiveprinciples relating to time clocks may also be applied to other portableswitching devices such as power strips, lamp holders, etc., as well aslocal switching devices as described below.

Some of the inventive principles of this patent disclosure relate to theuse of a local switching device in a wireless occupancy sensing system.A local switching device may have a structure similar to any of theembodiments of portable switching devices described above with respectto FIG. 1 through FIG. 6. Rather than being portable, however, it may belocal in the sense that it may be connected to a load without anyadditional building wiring between the local switching device and theload. For example, the local switching device may be implemented with areceptacle that is mounted in a wall outlet and configured to receivethe wireless signal from the occupancy sensor. The switching devicecontrols the flow of power to a load that is plugged in to thereceptacle in response to the wireless signal.

FIG. 13 illustrates an embodiment of a local power switch for a wirelessoccupancy sensing system according to some of the inventive principlesof this patent disclosure. The embodiment of FIG. 13 is configured as awall outlet having a duplex receptacle 160. A mounting plate 158 enablesthe entire assembly to be mounted in a standard electrical wall box. Thepower switch, switch control logic, signal processing circuitry (ifany), etc., may be enclosed in a housing 156. Power connections to theswitch may be through pigtail wire leads 164 which may include hot,neutral, and ground connections for, e.g., a 120 VAC branch circuit.

The power switch inside the housing controls the flow of power from thewire leads to the duplex receptacle 160 in response to a wireless signalfrom an occupancy sensor received by a wireless receiver 162. A dial 166may be included to enable the user to manually set a custom delay time.In this embodiment, the dial is located on the face mounting plate 158so that it can be adjusted by removing the wall plate, but withouthaving to remove the assembly from the wall box. In other embodiments,the dial or other user interface may be located directly on thereceptacle, on or inside the housing, etc.

The wireless signal from the occupancy sensor may be implemented as ahigh-level occupancy signal, a low-level detector signal, or somecombination thereof. The embodiment of FIG. 13 may include any suitableamount of signal processing functionality depending on the type ofwireless signal transmitted by the occupancy sensor.

Although the embodiment of FIG. 13 is illustrated as a wall outlet witha receptacle, a local switching device may also be embodied in otherforms such as a power pack, a screw-base lamp holder, etc.

FIG. 14 illustrates another embodiment of a local power switch for awireless occupancy sensing system according to some of the inventiveprinciples of this patent disclosure. The embodiment of FIG. 14 isconfigured as a power pack that may be mounted directly to a lightfixture, exhaust fan, space heater, or other electrical load. The powerpack includes an enclosure having two housing halves 168 and 170. Aconduit connection 172 molded into the housing halves provides amechanical connection to a load such as a light fixture. The power packmay include one or more power switches to control the flow of power toone or more loads. The switches may operate at relatively high voltagessuch as 120, 240 or 277 VAC as is commonly used in building wiringsystems, although some embodiments may operate at other voltages such as12 VDC, e.g., for landscape wiring. The power pack may also include apower supply to convert high-voltage power to a low-voltage source foroperating the internal circuitry.

The power switch inside the housing controls the flow of power to theload in response to a wireless signal from an occupancy sensor receivedby a wireless receiver 174. A dial 176 may be included to enable theuser to manually set a custom delay time.

The wireless signal from the occupancy sensor may be implemented as ahigh-level occupancy signal, a low-level detector signal, or somecombination thereof. The embodiment of FIG. 14 may include any suitableamount of signal processing functionality depending on the type ofwireless signal transmitted by the occupancy sensor.

The inventive principles of this patent disclosure have been describedabove with reference to some specific example embodiments, but theseembodiments can be modified in arrangement and detail without departingfrom the inventive concepts. For example, some of the embodiments havebeen described in the context of lighting loads, but the inventiveprinciples apply to other types of electrical loads as well. Any of thecircuitry and logic described herein may be implemented in analog and/ordigital hardware, software, firmware, etc., or any combination thereof.As another example, some of the embodiments have been described in thecontext of interior building spaces, but the inventive principles applyto exterior or hybrid spaces as well. Such changes and modifications areconsidered to fall within the scope of the following claims.

1. A system comprising: a wireless receiver to receive a wireless signalfrom an occupancy sensor; and at least one power switch to control powerto at least one load in response to the wireless signal; where thewireless receiver and power switch are included in a local switchingdevice; and where the local switching device comprises a power packhaving a housing, a power supply to convert high-voltage power to alow-voltage source for operating internal circuitry in the power pack,and switch control logic to implement an unoccupied delay time.
 2. Thesystem of claim 1 where the power pack further includes a user interfacecoupled to the switch control logic to enable a user to set theunoccupied delay time.
 3. The system of claim 2, wherein the userinterface comprises one of a dial, a push-button switch, and a keypadwith full text display.
 4. The system of claim 1 wherein the loadcomprises one of a light fixture, an exhaust fan, a space heater andlandscape wiring.
 5. The system of claim 1, wherein the wirelessreceiver comprises a wireless receiver to receive a high-level occupancysignal.
 6. The system of claim 1, wherein the wireless receivercomprises a wireless receiver to receive a low-level detector signal. 7.The system of claim 1, wherein the power switch operates at one of 120,240 or 277 VAC.
 8. The system of claim 1, wherein the power switchoperates at one of 12 VDC and 24 VDC.
 9. The system of claim 1, whereinthe power switch comprises one of an air-gap relay, solid state relay,an SCR based switch, a triac based switch, a transistor based switch, apower switch of discrete steps, and a power switch with continuousswitching.
 10. A power pack comprising: a housing; a wireless receiverlocated within the housing, the wireless receiver being adapted andconfigured to receive a wireless signal from an occupancy sensor; apower switch located in the housing, the power switch being adapted andconfigured to control power to a load in response to the wirelesssignal; and switch control logic located in the housing, the switchcontrol logic implementing an unoccupied time delay.
 11. The power packof claim 10, wherein the power switch turns on a flow of power to theload in response to receiving the wireless signal from the occupancysensor.
 12. The power pack of claim 11, wherein the power switch turnsoff the flow of power to the load after delaying for the unoccupied timedelay after no longer receiving the wireless signal from the occupancysensor.
 13. The power pack of claim 10, further comprising a userinterface coupled to the switch control logic to enable a user to setthe unoccupied time delay.
 14. The power pack of claim 13, wherein theuser interface comprises one of a dial, a push-button switch, and akeypad with full text display.
 15. The power pack of claim 10, furthercomprising a conduit connection extending from the housing forconnecting to a light fixture.
 16. The power pack of claim 10, whereinthe power switch operates at one of 120, 240 or 277 VAC.
 17. The powerpack of claim 10, wherein the power switch operates at one of 12 VDC and24 VDC.
 18. The power pack of claim 10, wherein the power switchcomprises one of an air-gap relay, solid state relay, an SCR basedswitch, a triac based switch, a transistor based switch, a power switchof discrete steps, and a power switch with continuous switching.
 19. Thepower pack of claim 10, further comprising a power supply located in thehousing for converting high-voltage power received by the power pack toa low-voltage source for operating internal circuitry in the power pack.20. A power pack comprising: a housing; a wireless receiver locatedwithin the housing, the wireless receiver being adapted and configuredto receive a wireless signal from an occupancy sensor; a power switchlocated in the housing, the power switch being adapted and configured tocontrol power to a load in response to the wireless signal, the powerswitch being adapted and configured to turn on a flow of power to theload in response to receiving the wireless signal from the occupancysensor; a power supply located in the housing, the power supplyconverting high-voltage power received by the power pack to alow-voltage source for operating internal circuitry in the power pack;and switch control logic located in the housing, the switch controllogic implementing an unoccupied time delay such that the power switchturns off the flow of power to the load after delaying for theunoccupied time delay after no longer receiving the wireless signal fromthe occupancy sensor.